Conduit box



Jan. 16, 1951 J, DESLOGE 2,538,088

CONDUIT BOX Filed Jan. 29, 1949 INVENTOR JOSEPH DESLOGE xii ATTORNEYPatented Jan. 16, 1951 UNITED STATES PATENT OFFICE CONDUIT BOX JosephDesloge, Florissant, Mo., assignor to Killark Electric ManufacturingCompany, St. Louis, Mo., a corporation of Missouri Application January29, 1949, Serial No. 73,588

2 Claims. 1 1

This invention relates in general to certain new and useful improvementsin conduit boxes and methods of making the same.

Heretofore it has been the practice to fabricate conduit boxes byconventional casting procedure, employing sand molds and sand cores.Obviously, the preparation of cores is both time-consuming and expensiveand has been found to result in castings which contain rough spots andfrequently must be rejected for that, as well as other reasons. It hasfurthermore been found in actual practice that conduit boxes of theconventional type have various undercut surfaces which collect dirt andmoisture and needlessly add to the weight of metal in the boxes withoutcontributing to the structural strength thereof.

It is, therefore, the primary object of the present invention to providea conduit box uniquely de-- signed to eliminate substantially all of theundercut surfaces and areas encountered in conventional conduit boxes,thereby materially improving the functional characteristics of the boxand, at the same time, reducing the cost thereof.

It is a further object of the present invention to provide a conduit boxand method of making the same whereby light weight alloys may readily beemployed and the use of expensive or complicated sand cores may beeliminated.

It is an additional object of the present invention to provide a conduitbox uniquely so designed as to permit the use of retractable cores,thereby materially simplifying the manufacturing operations andproviding a conduit box having improved structural characteristics.

Wth the above and other objects in View, my invention resides in thenovel features of form, construction, arrangement, and combination ofparts presently described and pointed out in the claims.

In the accompanying drawing- Figure 1 is a fragmentary top plan View ofa conduit box constructed in accordance with and embodying the presentinvention;

Figures 2 and 3 are sectional views taken along lines 2-2 and 33,respectively, of Figure 1;

Figure 4 is a top plan view of a modified form of conduit boxconstructed in accordance with and embodying the present invention;

Figure 5 is a transverse sectional view taken along line 5-5 of Figure4;

Figure 6 is a top plan view of a further modifled form of conduit boxconstructed in accord Figure 11 is a sectional view taken along line IIH of Figure 10.

Referring now in more detail and by reference characters to as drawing,which illustrates practical embodiments of the present invention, Adesignates a conduit boxcomprising a unitary cast open-topped shell-likehousing 9 integrally including straight parallel side walls 2, 3,connected by outwardly curved end walls t and a transversely extendingbottom wall 5, defining a cavity a for housing an electrical switch,receptacle 01' other similar device. Also formed integrally with andprojecting outwardly on either side from the end walls 4 are axiallyaligned tubular conduit hubs 6, which open at their interior ends intothe housing and are internally threaded as at 7 for receiving thethreaded end of a length of conduit pipe (not shown).

It should be particularly noted, as may be seen by reference to Figures2 and 3, that the interior faces of the side walls 2, 3, and end walls 4are sloped inwardly and downwardly and joined to the bottom wall by ashort radius, as at r, so as to provide the interior without overhangingledges or back-drafts from which a permanent retract able core will drawreadily. Finally, the side walls t are provided centrally of theiroutwardly presented or exposed faces with tapped holes a by whichconventional cover plate retainer screws (not shown) may be suitablyinstalled.

If desired, a modified form of conduit box A may be provided, which issubstantially identical in all respects with the previously describedconduit box A except that it is provided with arcuate end walls 4'having relieved areas symmetrically disposed on opposite sides of thetapped hole 8' in the formation of recesses 9 which extend downwardly inthe direction of the bottom wall 5, terminating somewhat above theopening It from the tubular conduit hub 6-. The side walls of;

the recesses 9 have slight inward and downward angles of convergencevery much in the same manner as previously described with respect to thewalls 2, 3, 4, of the conduit box A, so that a retractable core may beused and will freely withdraw from the interior of the conduit box A. Ithas been found that, by the employment of the recesses 9 in the designof the conduit box A, it is possible to produce a conduit boX ofsomewhat lighter weight without sacrificing to any material degree thestrength or efficiency thereof.

If desired, a further modified form of conduit box B may be providedcomprising a rectangular box-like open-topped casting integrallyincluding straight parallel side walls l i, [2, transversely connectedby straight parallel end walls 13 and a transversely extending bottomwall 4, defining a cavity 1). Also cast integrally with, and extendingaround the peripheral edges of the walls I 6, l2, l3, is a continuousoutwardly turned flange l which in relatively narrow along the walls Ii, l2, and is relatively wide along the transversely extending end wallsit. Also formed integrally with the end walls I3, and projectingoutwardly from the outer faces thereof and downwardly from. the underface of the wide transversely extending portions of the flange 15, areintegrally cast hubs it which are axially drilled, counterbored, andtapped to provide sockets I1 internall threaded for receiving conduitpipe or tubing (not shown). As will be noted by reference to Figures '2and 8, the inside faces of the walls H, l2, l3, and the outer side facesof the hubs H5 are provided with slight angles of convergence or inwardtaper, as it may be called, to permit the use of retractable permanentcores which may be readily withdrawn therefrom and also to permit readywithdrawal of the entire casting B from the mold, so that, if desired, apermanent mold may also be used.

The hubs it are finally provided in their upper portions above the pipesockets H with tapped holes M3 for receiving conventional cover plateattachment screws (not shown), and symmetrically arranged on either sideof the tapped holes i3 are'downwardly and inwardly tapered recesses ii?"which open later lly into the cavity 1) and terminate in arcuatebottomed walls to concentric with and located in radially outwardlyspaced relation to the pipe sockets l? for eliminating excess weight ofmetal and preventing the formation of cooling stresses which ordinarilyoccur in the heavy portions of castings of the type here underdiscussion. It will be noted in this connection that the recesses is aretapered very much in the same manner as the inner faces of the walls ii,E2, 52, so as to be capable of being formed by suitable projectionswhich are a part of a single retractable core.

If, desired, a further modified form of conduit box C may be provided,comprising a somewhat circular box-like open topped casting having asubstantially cylindrical annular side wall the interior face of whichis tapered inwardly and downwardly toward a flat bottom wall 2!,defining a cavity 0. Formed integrally upon and projecting outwardlyfrom diametrally outward position upon the exterior face of the sidewall are mounting cars 22., which are substantially flush upon theirunder face with the under face of the bottom wall Also formed integrallywith the side wall 29 at 90 intervals therearound are hubs 2-3 which arethicknened and provided with interior and exterior faces substantiallyperpendiculanto the bottom wall 25. The hubs'ZB- are furthermore drilledand tapped for receiving the threaded ends of either conduit pipe orconduit receiving fittings, as be desired.

Upon their under faces, each 23 extends upwardly in the provision of anintegrally cast boss 24 which is drilled and tapped as at 2?: forconventionally receiving screws by which a receptacle or otherelectrical device may be secured in place. It should be particularlynoted in this connection that all interior and exterior surfaces of theconduit box C are arranged to eliminate overhanging ledges orback-drafts so that a permanent retractable core may be simply andexpedientiy used and entire design is thus readily adaptable tofabrication in a die casting machine or by sand casting methods by theuse of permanent cores.

It has been found that conduit bones constructed. in accordance with andembodying the present invention unusualiy strong and durable and are ofa design whic lends itsel readily to much more economical methods offabrication than heretofore have been possible. in fact, theconduitboxes of the present invention are readily adaptable tomechanical mother of casting, such as die casting machines, for example.

a central cavity defined by a bottom portion and side walls and endwalls, said side and end walls being sloped inwardly and downwardlytoward the bottom portion in a converging manner and being joined to thebottom portion by a radius, the said end walls being made thicker thanthe side walls and at least one end wall being pro vided upon itsoutwardly presented face with an integrally cast projecting hub, saidhub being counterbored to provide a conduit-receiving opening, each ofsaid. thickened end Walls having a pair of downwardly and inwardlytapered recesses opening on its inner face, the bottom of the recesseson the said hub-bearing end wall being formed by arcuate walls locatedabove the bottom portion of the conduit box and being substantiallyconcentric with the conduit-receiving opening, the walls of saidrecesses defining projecting spaced pillars the end faces of which liein the plane of the op n-top.

2; A substantially rectangular conduit box comprising a cast metal bodyhaving an open-top and a central cavity defined by a bottom portion andside walls and end walls, said side and end walls being sloped inwardlyand downwardly toward the bottom portion in a converging manner andbeing joined to the bottom portion by a radius, the said end walls beingmade thicker than the side walls and at least one end wall beingprovided upon its outwardly presented face with an integrally castprojecting hub, said hub being counterbored to provide aconduit-receiving opening, each of said thickened end walls having apair of downwardly and inwardly tapered recesses opening on its innerface, the bottom of the recesses on the said hub-bearing endwall beingformed by arcuate walls located above the 76 bottomportion of theconduit box and being sub- 5 stantially concentric with theconduit-receiving opening, the walls of said recesses defining ro-J'ecting spaced pillars the upper end faces of which lie in the plane ofthe open-top, said upper end faces of the pillars being provided withinternally threaded openings adapted for receiving fastening elements.

JOSEPH DESLOGE.

REFERENCES CITED UNITED STATES PATENTS Name Date Hinsdill Apr. 9, 1907Number Number Number Name Date Raymond Dec. 1, 1908 Ward May 20, 1919Boyton et al May 15, 1928 Shickluna Nov. 19, 1929 Mever Dec. 2, 1930Steber Aug. 25, 1942 Popp Mar. 21, 1944 FOREIGN PATENTS Country DateGreat Britain June 11, 1925 Great Britain Oct. 8, 1931

